JOURNAL OF PERSONALITY ASSESSMENT, 1998,70(3), 514-534 Copyright O 1998, Lawrence Erlbaum Associates, Inc. The Rorschach Schizophrenia Index (SCZI): An Examination of Reliability, Validity, and Diagnostic Efficiency Mark J. Hilsenroth Department of Psychology University of Arkansas J. Christopher Fowler Austen Riggs Center Stockbridge, Massachusetts Justin R. Padawer Department of Psychology University of Tennessee In this study, we investigate the reliability, validity, and diagnostic efficiency of the Rorschach Schizophrenia Index (SCZI) in relation to the accurateidentificationof pa- tients diagnosed with Diagnostic and Statistical Manual of MentalDisorders (4th ed. [DSM-IV], American Psychiatric Association, 1994) schizophrenia or other psy- chotic disorder (PD) according to the methodological recommendations offered by Wood, Nezworski, and Stejskal (1996). Seventy-eight patients who were found to meet DSM-IVcriteria for a PD or Axis I1 disorder (PD = 33; borderline personality disorder = 23; Cluster A personality disorders = 9; Cluster C personality disorders = 13) and 50 nonclinical participants were compared on the SCZI. The results of this study indicate that the SCZI is internally consistent and can be reliably scored. In ad- dition, the SCZI was used effectivelyin differentiating PD patients from patients with an Axis 11 disorder and from the participantsin the nonclinical sample.Also, the SCZI variable was found to be empiricallyrelated to the presence of a DSM-IVdiagnosis of PD. Finally, this variable could be employed for classification purposes in ways that were clinically meaningful in the diagnosis of a PD. Conceptual and methodological issues are discussed in relation to the assessment of psychosis. Clinicians with varied theoretical perspectives have approached the differential di- agnosis of psychotic dsorders (PD; Diagnostic and Statistical Manual of Mental Disorders [3rd ed.; DSM-ZZZI American Psychiatric Association [APA], 1980; Downloaded by [Newcastle University] at 08:26 21 December 2014